Department of Bioprocesses and Biotechnology, School of Pharmaceutical Sciences, São Paulo State University (UNESP), Rodovia Araraquara-Jaú/km 01, Araraquara, SP, 14800-903, Brazil.
Bioprocess Biosyst Eng. 2019 Jul;42(7):1235-1246. doi: 10.1007/s00449-019-02121-w. Epub 2019 Apr 17.
This work studied the effect of the cation alkyl chain length of 1-alkyl-n-methylimidazolium chloride ([Cmim]Cl)-based ILs on the activity of Aspergillus niger lipase. First, the lipase activity in the presence of different ILs concentration over time was determined. ILs with shorter cation alkyl side chain length, namely [Cmim]Cl and [Cmim]Cl, promoted an increase of lipase activity; while, [Cmim]Cl, depending on its concentration, maintained or decreased the enzyme activity. In the presence of ILs with longer cation alkyl chain length, i.e., [Cmim]Cl and [Cmim]Cl, the lipase relative activity was reduced with 0.1 (%v/v) and until suppressed ([Cmim]Cl at 0.3 (%v/v)) as a result of irreversible changes in its secondary structure. Fluorescence and circular dichroism spectroscopy analysis confirmed the results achieved. These findings show that [Cmim]Cl-based ILs can exert different behavior on the lipase' activity (enhance, maintain or even inhibit) and structural conformation, depending on the cation alkyl chain length and their relative concentration.
本工作研究了 1-烷基- N-甲基咪唑氯([Cmim]Cl)基离子液体([ILs])中阳离子烷基链长度对黑曲霉脂肪酶活性的影响。首先，测定了不同 ILs 浓度随时间变化时脂肪酶的活性。具有较短阳离子烷基侧链长度的 ILs，即[Cmim]Cl 和[Cmim]Cl，促进了脂肪酶活性的增加；而[Cmim]Cl 则根据其浓度维持或降低了酶活性。在具有较长阳离子烷基链长度的 ILs 存在下，即[Cmim]Cl 和[Cmim]Cl，脂肪酶相对活性随着 0.1(%v/v)而降低，并且由于其二级结构的不可逆变化而受到抑制([Cmim]Cl 在 0.3(%v/v))。荧光和圆二色性光谱分析证实了所得到的结果。这些发现表明，基于[Cmim]Cl 的 ILs 可以根据阳离子烷基链长度及其相对浓度对脂肪酶的活性(增强、维持甚至抑制)和结构构象产生不同的作用。
